The animal and tissue procurement core is responsible for generating the canine model of cardiac dyssynchrony and/or tachypacing-induced dilated cardiomyopathy. Adult mongrel dogs weighing approximately 25 kg are employed in this study. Dyssynchrony is generated by radiofrequency ablation of the left bundle (or right bundle in a sub-set of studies). In addition, dyssynchrony can be induced by single-point pacing of the RV or LV free-wall - and this variant can also be utilized for some of the molecular/cellular analyses. Cardiac failure is induced by tachycardia pacing over a period of 3-6 weeks depending on the protocol. Cardiac resynchronization is achieved by converting 3-weeks of rapid atrial pacing in the setting of an established conduction delay - with 3-4 weeks of bi-ventricular pacing of left ventricular free wall and right ventricles. The primary aims of this Core are to 1) Perform the surgical and electrophysiologic procedures required to induce dyssynchrony with and without cardiac failure. Provide chronic instrumentation for mechanical and energetic analyses as required by the individual projects. 2) Maintain all chronic care of the animal, providing serial physiologic assessment as required, including coordinating echocardiographic analysis, intermittent pressure measurements, etc.. 3) Coordinate veterinary support on a per-need basis to assure optimal care and maintenance of the animals, catheters, repairing fractured or damaged pacing leads, etc.. 4) Perform terminal study - including rapid procurement of myocardial tissues used to wedge and cellular preparations, and rapid processing of frozen materials required for molecular and histochemistry analyses.